i would like to apologize to what i had replied on Prove it's answer... i never meant to be so mean... my point was, i didn't understand what he had been solving, i mean the answer itself is too difficult for me to understand , i was thinking that i would be solving too long like adding from 1 to 1999 consecutive numbers because it is summation ... i didn't know how it would go to 1999 + 1 - 1/2000 .... sorry i really cannot get how it would become like that... sorry hope you guys understand... it was just miscommunication.